Jack Osbourne dresses baby girl up as grandpa Ozzy

Black Sabbath rocker Ozzy Osbourne has a mini-me. Baby granddaughter Pearl showed just how much she looks like the musician when her dad, Jack, the youngest child of Ozzy and wife Sharon Osbourne, dressed the little girl up in a costume complete with long, black wig, crucifix necklace and grandpa's signature round-frame glasses.

"The Princess of Darkness," Jack Osbourne tweeted in a photo of his little 18-month-old lady.

The Black Sabbath frontman is currently touring in South America, but has shown much support for his son on "Dancing With the Stars" before he went out of town. Ozzy Osbourne and wife Sharon, along with daughter and "Fashion Police" co-star Kelly, have been in the audience of the ballroom bash each week to cheer the 27-year-old in his quest for mirror ball glory.

Jack, who was diagnosed with multiple sclerosis just two weeks after Pearl was born, told ABC News that he wanted to participate in the dance competition to bring attention to the disease. "There's not that many young people that have the disease that are in entertainment and do speak up about it," he said when the latest cast was revealed.

MS is a disease of the nervous system that impacts the brain and spinal cord, causing messages from the brain to the body to be slowed or blocked.

Jack Osbourne told ABC News prior to the show's Sept. 16 premiere that "Physically right now, I'm good." And so far, he's done quite well on "DWTS," with the judges heaping praise on him in the first week.